MORNING LOWS
-1 Lafayette, Anderson, Kokomo, Tipton
0 Indy and Bloomington
1 Muncie
2 Terre Haute
HEADLINES
– Cold Weather Advisory in effect through Wednesday morning.
– Wind chills of 10 to 20 below expected through Wednesday.
– Scattered flurries with a few snow showers tonight.
– Moderating temperatures Wednesday onward, though still below normal.
– Slight chance of flurries or light snow showers Thursday into Thursday night.
TODAY’S MAP
NWS INDIANAPOLIS TECHNICAL DISCUSSION
Today... Sunshine will combat the cold airmass today and should bring temperatures back to around 10 to near 15 degrees. Winds of 5 to 15 mph with some higher gusts will make it feel colder. Wind chills will warm above Cold Weather Advisory criteria for some areas today, but will let the Advisory continue to keep messaging simple. Later this afternoon, clouds will increase ahead of another upper wave and reinforcing shot of cold air. Tonight... Forcing will move in this evening and continue overnight as an upper trough works its way into the area. A reinforcing shot of colder air will accompany it. Moisture is limited with this system, but with some lift and moisture in the dendritic growth zone, scattered flurries and a few snow showers will likely be squeezed out. Will have some slight chance PoPs for parts of the area with a mention of flurries elsewhere, spreading from northwest to southeast during the night. The light and fluffy snow may accumulate a couple of tenths in some areas. Clouds will help keep temperatures a little warmer than the previous night, but winds will still produce wind chills of at or below -10 for much of the area. Thus will continue the Advisory as is. && .LONG TERM (Tuesday through Sunday)... Issued at 300 AM EST Mon Jan 20 2025 We`ll be transitioning out of the arctic pattern currently in place with temperatures to return to normal by the end of the week. Tuesday night into Wednesday looks to be our last night of truly cold conditions. There remains quite a spread within guidance regarding how cold it gets, with one camp showing lows well into the negatives (ECMWF and GEM) and the other keeping lows near or above zero (GFS and associated models). Right off the bat the GEM appears way too cold, so it will be discounted. The factors contributing to the temperature forecast will be how efficient radiative processes (dependent on cloud cover and wind speed) are and how quickly warm air advection begins during the night. Right now, the surface high center looks to pass through Indiana late in the day Tuesday and early Wednesday. Return flow on the back side of the high allows winds to become southerly. Warm air advection behind the high appears quite robust...with 850mb temps climbing from -25C Tuesday afternoon to -10C by 12Z Wednesday. Additionally, a potent low-level jet (LLJ) develops as a passing wave to our north tightens the MLSP gradient and induces a strong mass response. Radiative process might be strong early in the night as winds remain light and lingering daytime clouds dissipate...but these processes could be countered more effectively (by mixing and a light southerly wind) as the night progresses. Therefore, temperatures could plunge sharply after sunset Tuesday before leveling off. We will keep our eastern and northeastern counties the coldest since they will feel the effects of the LLJ and warm air advection the least...and we will keep our central and southwestern counties a bit warmer than previous forecast cycles. Regardless, temperatures are still expected to be very cold with lows between 0 to 5 degrees above from Indy southwestward and -8 to 0 north and east. On Wednesday, the warm air advection and LLJ mentioned above fully enter into Indiana. Diurnal mixing and a tightening MSLP gradient should promote gusty SSW winds. Such patterns tend to be a bit windier than what blended guidance suggests, so we will bump winds and wind gusts up slightly during the daylight hours Wednesday. With this in mind, our forecast now shows wind gusts up near 30mph from Indy northwestward. Even with the robust warm air advection mentioned above, our high temperatures will "only" reach low to mid 20s. With those temperatures a 20-30mph wind creates wind chills in the single digits, so Wednesday will still feel very cold. The wave mentioned above should do more than just induce warm air advection. Some moisture looks to be present and enough lift may materialize to generate isolated snow showers and flurries across our northwestern counties. Most of this activity currently appears to be in Illinois and northern Indiana, however. Additionally, a secondary wave is modeled to pass through on Thursday with another round of light snow showers or flurries. We maintain low PoPs added by the day shift. Ensembles are showing a more active pattern by the weekend with possible precipitation chances. By this point, continued breakdown of the upper-level trough and air mass moderation should allow highs to be back to normal. As such, precipitation type issues could come into play should a system approach from the southwest. There remains little coherency within guidance so confidence is very low for any particular model solution.
INDY SEVEN DAY FORECAST
COLD WEATHER ADVISORY until 10am Wednesday.
Today: Sunny. Wind gusting to 20 mph in the afternoon. Chills as low as -15. High 13.
Tonight: Partly cloudy. Chills as low as -15. Low 3.
Tuesday: Partly sunny. Sub-zero chill. High 9.
Tuesday Night: Mostly clear. Chills as low as -15. Low 0.
Wednesday: Partly sunny. Chills below zero and in single digits. High 23.
Wednesday Night: Partly cloudy. Low 16.
Thursday: Partly to mostly cloudy. High 31.
Thursday Night: Mostly cloudy, with a few snow showers. Low 16.
Friday: Partly sunny. High 28.
Friday Night: Partly cloudy. Low 20.
Saturday: Partly sunny. High 38.
Saturday Night: Snow showers after midnight. Low 26.
Sunday: Snow and rain showers. High 36.

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